Diesel Controls

California and the EPA should be commended for taking overdue steps to clean up diesel trucks (Oct. 7). But your assertion that a new diesel truck will be “virtually exhaust-free” is misleading. Even with these tougher standards, a diesel truck will emit 200 times the smog-forming nitrogen oxides and 50 times the soot of a new car over its lifetime. Public health organizations have linked diesel soot to cancer in humans.

Even with tack-on technologies cleaning up their exhaust, diesel trucks are a longshot for meeting truly “near-zero” emission standards. In the race for clean air, inherently clean technologies, like natural gas and fuel cells, are the safest bets to reduce air pollution.

CANDACE J. MOREY

Transportation Analyst

Union of Concerned Scientists

Berkeley